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Why Experts Get the Future Wrong

What does the future hold? To answer that question, human beings have looked to stars and to dreams; to cards, dice and the Delphic oracle; to animal entrails, Alan Green­span, mathematical models, the palms of our hands. As the number and variety of these soothsaying techniques suggest, we have a deep, probably intrinsic desire to know the future. Unfortunately for us, the future is deeply, intrinsically unknowable.

This is the problem Dan Gardner tackles in “Future Babble: Why Expert Predictions Are Next to Worthless, and You Can Do Better.” Gardner, a Canadian journalist and author of “The Science of Fear,” takes as his starting point the work of Philip Tetlock, a professor at the University of Pennsylvania. Beginning in the 1980s, Tetlock examined 27,451 forecasts by 284 academics, pundits and other prognosticators. The study was complex, but the conclusion can be summarized simply: the experts bombed. Not only were they worse than statistical models, they could barely eke out a tie with the proverbial dart-throwing chimps.

The most generous conclusion Tetlock could draw was that some experts were less awful than others. Isaiah Berlin once quoted the Greek poet Archilochus to distinguish between two types of thinkers: “The fox knows many things, but the hedgehog knows one big thing.” Berlin admired both ways of thinking, but Tetlock borrowed the metaphor to account for why some experts fared better. The least accurate forecasters, he found, were hedgehogs: “thinkers who ‘know one big thing,’ aggressively extend the explanatory reach of that one big thing into new domains” and “display bristly impatience with those who ‘do not get it,’ ” he wrote. Better experts “look like foxes: thinkers who know many small things,” “are skeptical of grand schemes” and are “diffident about their own forecasting prowess.”

To his credit, Gardner is a fox. His book, though, is somewhat hedgehoggy. It knows one big thing: that the future cannot be foretold, period, and that those who try to predict it are deluding themselves and the rest of us. In defense of that theory, Gardner dips into the science of unpredictability and the psychology of certainty. And he provides case studies of failed prophets — a kind of hedgehog highlight reel, in which the environmental scientist Paul Ehrlich, the historian Arnold Toynbee and the social critic James Howard Kunst­ler come in for a particularly hard time.

This schadenfreude-fest can be good fun. Gardner leaves plenty of prognosticators squirming on history’s thumbtack, like the British journalist H. N. Norman, who argued, in early 1914, that “there will be no more wars among the six Great Powers.” And throughout this terrain, Gardner is an able tour guide. That’s a common analogy in reviews, but I mean it here as literally as a figurative claim can be. Like the guy who leads 200 people a day around London, Gardner is knowledge­able about the major attractions, cheerfully conversational, deliberately inoffensive and fond of jokes pitched at the chuckle range.

How you feel about his book will therefore depend on two things. The first is how much you like being led around to information, as opposed to getting lost, finding your bearings and working up a sweat. The second is whether you’ve already been to this destination. Here Gardner faces a challenge, and not just because Tetlock’s own book, “Expert Political Judgment,” is outstanding. Many recent works explore similar ground, so if you’re in Gardner’s target audience, you’ve most likely encountered much of his material. Are you familiar with hindsight bias or groupthink? Can you define “cognitive dissonance” or “heuristic”? Ever heard of Stanley Milgram’s fake electric shock experiments? If so — well, the future may not be predictable, but this book will be.

Competition is not its own criticism, of course, but Gardner struggles to distinguish himself. As a writer, he serves up a basically good meal with a grating of grating. Witness his fondness for overdetermined analogies. A video about the 2008 housing-market disaster “spread like a California wildfire in an abandoned housing development.” The 2003 invasion of Iraq “left failed predictions lying about the landscape like burnt-out tanks.”

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Illustration by Pietro Corraini

More worrisome than the literary lapses are the intellectual ones. First, Gardner repeatedly fails to distinguish between different kinds of forecasters — e.g., Ehr­lich and the evangelist Hal Lindsey. “Since rational people don’t take seriously the prognostications of Mysterious Madam Zelda or any psychic, palm reader, astrologer or preacher who claims to know what lies ahead,” he writes, “they should be skeptical of expert predictions.”

Undoubtedly we should be skeptical, but not for that reason. Just because a policy analyst and Madam Zelda both mispredict the future doesn’t make their predictions equivalent. The analyst’s prediction is moored in theory and evidence; if all other variables could be controlled, Fact A could cause Forecast B. (Inflation today could increase unemployment tomorrow.) Of course, all other variables can’t be controlled, and so the analyst may be wrong. Religious and occult predictions, however, boast no causal logic whatsoever. (“You will meet a tall, dark stranger because . . . I see him in my crystal ball”?) Even when they’re right, they’re wrong.

To ignore this difference is to stray perilously close to anti-intellectualism. And Gardner, despite his better impulses, drifts that direction in other ways as well — for instance, by pitting “all the smart people” against “ordinary Americans.” Wait: Ordinary Americans aren’t smart? Smart people aren’t real Americans? Such distinctions aren’t just invidious. They also dodge the real issue, which is that expertise and intelligence are not intellectually or morally equivalent to charlatanism. Indeed, they often serve us exceptionally well.

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More troubling still, Gardner perpetuates misunderstandings about the human mind. “We live in the Information Age,” he writes, “but our brains are Stone Age.” That is, we make mistakes because our minds are eons out of date, a jumbled mess of “kludges” ill-suited to modern life.

This idea is the Noble Savage of pop neuroscience: a catchy, culturally convenient notion that is flat wrong. It’s easy to tell Just So stories about why we are the way we are, but they can’t be proved, and they often collapse under even mild scrutiny. (So in the Stone Age, when our brains were perfectly calibrated for our environment, we never made mistakes?)

Gardner, for all his concern about prediction, has no qualms about retrodiction, even of the distant, unknowable past. He writes enthusiastically about how we are “hard-wired” for this or that trick — say, to crave certainty. Never mind that he himself seems quite comfortable with doubt. Even if the brain is in some sense hard-wired (and given what we know about plasticity, the analogy is questionable), those wires unfold to millions of miles and possess an estimated 1,000,000,000,000,000 connections. That’s some fuse box. And that’s why neuroscientists, like the foxes Gardner professes to admire, exercise caution in their claims about the brain.

What is most frustrating about all this iffy evolutionary psychology is that it represents Gardner’s only real effort to understand why we obsess about the future. True, back in the day, we needed to predict whether the rustling in the bushes was a predator or dinner. But “What happens next?” is a deep and wide question, one that extends far beyond Paleolithic perils. It is about suspense, curiosity, tension, desire, death. Gardner touches almost none of that.

I want to like this book, because I share Gardner’s values and am sympathetic to his project. And clearly, skepticism and intellectual humility need all the champions they can get. But while “Future Babble” pays appropriate homage to the mysteries of the future, it gives short shrift to both the science of the human mind and the richness of the human experience.

FUTURE BABBLE

Why Expert Predictions Are Next to Worthless, and You Can Do Better

By Dan Gardner

305 pp. Dutton. $26.95.

Correction: April 10, 2011

A review on March 27 about “Future Babble: Why Expert Predictions Are Next to Worthless, and You Can Do Better,” by Dan Gardner, misstated the university affiliation of Philip Tetlock, whose work Gardner takes as his starting point. Tetlock is a professor at the University of Pennsylvania, not a retired professor at the University of California, Berkeley, where he previously worked.

Kathryn Schulz is the author of “Being Wrong: Adventures in the Margin of Error.”

A version of this review appears in print on March 27, 2011, on Page BR14 of the Sunday Book Review with the headline: What Lies Ahead?. Today's Paper|Subscribe